This invention relates to herbicidal pyridine, 1-oxides, and, more particularly, to 4- or 5-substituted pyridine, 1-oxides which exhibit selective pre-emergence control of weeds in certain crops such as sugarbeets, peas and tobacco.
U.S. Pat. No. 4,050,921 discloses 2-alkyl sulphinyl and 2-alkylsulphonylpyridine, N-oxides of the formula ##STR1## wherein R.sub.1 is hydrogen, alkyl, Ph or PhCH.sub.2 ;
R.sub.2 is hydrogen, alkyl, alkenyl, alkoxycarbonyl, among others; and PA1 n is 1 or 2 PA1 X is fluorine, bromine or chlorine; PA1 Y is fluorine, bromine or chlorine; and PA1 n is 0, 1 or 2.
and teaches their use as plant growth regulants.
U.S. Pat. No. 3,295,946 discloses compounds such as 2-(2,3,6-trichlorobenzylthio)pyridine, 1-oxide and 2-(polychlorobenzylthio)pyridine, 1-oxide and teaches a method of controlling vegetation which comprises applying thereto a phytotoxic concentration of such benzylthiopyridine oxides.
Neither reference indicates that the 4- or 5-substituted pyridine, 1-oxides of this invention would exhibit selective pre-emergence control of weeds.